Railway signaling apparatus



y 1939- L. o. GRONDAHL 2,159,524

RA ILWAY S IGNALING APPARATUS Original Filed May 17, 19:55

Ia 7 A1 i I Lam OJEZZIJIZ. BY a, I

HIS ATTORNEY Patented May 23, 1939 UNITED STATES PATENT OFFICE RAILWAY SIGNALING APPARATUS Original application May 17, 1935, Serial No.

22,052, now Patent No. 2,108,483, dated February 15, 1938.

Divided and this application September 16, 1937, Serial No. 164,186

11 Claims.

My invention relates to railway signaling ap-- paratus, and more particularly to apparatus of the type involving track circuits.

One of the objects of my invention is to provide novel and improved means to insure the release of a track relay when a vehicle or train enters the associated section.

The present application is a division of my application Serial No. 22,052, filed May 17, 1935,

now U. S. Patent No. 2,108,483, granted Feb. 15,

1938, forRailway signaling apparatus.

In the accompanying drawing, Figs. 1 to 3, inclusive, show various forms of track circuits, each embodying my invention. Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, the reference characters la and lb designate the rails of a stretch of railway track, which rails are divided by insulated joints ID to form track sections, only one of which is shown in the drawing and is designated AB. The track section AB is provided with a track circuit including a track relay TR connected across the rails la and l bat one end of the section in series with a front contact of an auxiliary relay Al, and the secondary winding of a track transformer T connected across the rails at the other end of the section. The auxiliaryrelay Al is held energized by a battery D '30 connected to the rail lb and to the corresponding rail of the adjacent section, separated by the insulator l0.

When a vehicle enters the section, a front wheel thereof momentarily shunts current from the relay Al which accordingly drops and opens the circuit of the track relay. The vehicle, while in the section, also maintains a shunt across the rails la and lb until the train clears the section. Once the track relay has released its armature, '4 the shunting action of the train will ordinarily 'be sufiiciently effective to prevent the track relay again picking up until the train clears the section. The limiting resistor l3 prevents short-circuiting of the battery D during such time as relay Al is shunted by the train.

The arrangement of Fig. 2 differs from that of Fig. 1 only in that the section junctions are staggered and the auxiliary battery D is connected across the opposite rails of adjacent sections. The auxiliary relay Al will accordingly deenergize as the train enters the section and will remain deenergized as long as a portion of the train occupies the space between the junctions of adjacent sections. After the train clears the junction, the usual shunting action of the train will come into play to prevent the picking up of the track relay until the train clears the section.

If it is desired to insure positively the dropping of the track relay irrespective of the end of the section entered, this may be accomplished by applying the apparatus at both ends of the track section. Such an arrangement is illustrated in Fig. 3. In this figure, the arrangement which is shown in Fig. 2 is modified by including a front contact of the auxiliary relay Al in the track feed circuit of the adjoining section BC. It will be evident then that when a train in section AB enters section BC, the auxiliary relay Al will open the feed circuit to the track relay of section BC so that the track shunt need be 15 only sufficiently effective to pervent the picking up of the track relay after Al has ceased to function. The movement of a train from section BC into AB will be effective in a manner similar to a corresponding movement as described in connection with Fig. 2, except that as the train leaves the section, the Al relay at the leaving end of the section will hold the track circuit open until the train clears the junction of the adjoining sections.

Although I have herein shown and described only a few forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without depart- 30 ing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a railway track section, a track circuit for said section including a first .35 source of current, the respective rails of the section and a track relay; a second circuit including a second source of current and a normally energized auxiliary relay connected from a rail of said section to a rail of an adjoining section elec- '40 trically separated by an insulated joint, and a front contact of said auxiliary relay included in said track circuit, whereby said auxiliary relay will respond to the shunting of current therefrom as the wheel of an approaching vehicle bridges A5 the insulated joint thus opening said front contact to insure the release of said track relay.

2. In combination with a railway track section separated from adjoining sections by insulated joints at the rail ends of adjoining sections 50 arranged in staggered relation to each other; a track circuit for said section including a first source of current, the rails of said section and a track relay; and a second circuit including a ,secondsource of current and a normally ener- 55 gized auxiliary relay connected to the two opposite rails of adjoining sections and having a front contact included in said track circuit opened when the operating'current for the winding of said auxiliary relay is shunted by the axles and wheels of an approaching vehicle as they bridge the opposite rails of adjoining sections to insure the release of said track relay.

3. In combination with a stretch of track divided into sections in which the rails of adjoining sections are insulated from each other with the one trafiic' rail of the adjoining sections having its insulated joint located slightly in advance of the other; a track circuit for one of said sections including a first source of current, the rails of such section and a track relay; a second circuit including a second source of current and anormally energized auxiliary relay connected to the opposite rails of the adjoining sections and having a front contact included in said track cir-' cuit, a third source of track circuit current for feeding the track relay of the adjoining section over the rails thereof and also including a front contact of said auxiliary relay; said auxiliary relay having its operating current shunted therefrom by the shunting action of the wheels and axle of a vehicle as it bridges the opposite rails of such adjoining sections to cause it to openits contacts to insure the release of the track relay of the section being entered.

4. In combination, a section of railway track, a source of track circuit current and a track relay each connected across the rails of said section, a second source of current connected from a rail of said section to a rail of an adjoining section separated from the first section by an insulated rail joint, a normally picked up auxiliary relay energized from said second source, and means controlled by said auxiliary relay efiective when said second source is shunted by a train for aiding the release of said track relay.

5. In combination, a section of railway track, a source of track circuit current and a track relay each connected across the rails of said section, a second source of current connected from a rail of said section to a rail of an adjoining section separated from the first section by an insulated rail joint, a normally picked up auxiliary relay energized from said second source, and a contact controlled by said auxiliary relay effective when said second source is shunted by a train for opening the connection of said track relay with a rail of said section.

6. In combination, a section of railway track, a source of track circuit current, a track relay energized from said source over the rails of said section, a second source of current connected from a rail of said section to a rail of an adjoining section separated from the first section by an insulated rail joint, the current from said second source being incapable of operating said track relay, a normally picked up auxiliary relay energized from said second source-and means controlledby said auxiliary relay effective when said second source is shunted by a train for aiding the release of said track relay.

'7. In combination, a section of railway track having an insulated rail joint at one end thereof, a source of track circuit current and a track relay each connected across the rails of said section, a second source of current connected around said insulated rail joint, a normally picked up relay effectively energized from said second tion, a second source of current connected around said insulated rail joint, a normally energized auxiliary relay also connected around said insulated rail joint, and means including a contact of said auxiliary relay for controlling the energization of. said track relay from said track circuit source.

9. In combination, a section of railway track, a source of track circuit current and a track relay each connected across the rails of said section, a second source of current connected from one rail of said section to the other rail of an adjoining section separated from the first section by an insulated rail joint, a normally picked up auxiliary relay energized from said second source, and means controlled by said auxiliary relay effective when said second source is shunted by a train for aiding the release of said track relay.

10. In combination, a first and a second adjoining section of railway track separated by insulated rail joints arranged in staggered relation to each other, a first anda second source of track circuit current for said respective track sections, a track relay energized from the rails of said first section, a third source of current connected to the two opposite rails of adjoining sections, a normally picked up auxiliary relay ene'rgized from said third source, and means controlled by said auxiliary relay efiective when said 7 third source is shunted by a train for governing the supply of current from said second source to said second section and for governing the energization of said track relay.

11. In combination with a railway track section; a track circuit having an insulated rail joint at one end thereof and including a source of current, a track relay, and the rails of the section; a second circuit including a second source of current and a normally energized auxiliary;

CERTIFICATE OF CORRECTION. Patent No. 2,159,52h. 'May 25, 1959.

of the above nungbered patent requiring correction 9.2. follows: Page 2, second column, line 7, claim 7, befor the word "relay"'1nsert auxiliary; and that Henr Van Arsdale (Seal) Acting Comm ssioner of Patents. 

